the assemblies showed CPL. In such case, the chiral element is from the nonemissive
gelator, while the fluorescence (comes or originates) from the nonchiral fluorophore.
The third case is the achiral chromophore without any chiral unit. In molecular state,
it does not show any CPL activity. However, upon gelation, symmetry breaking
occurs and the CPL could also be obtained.
In this chapter we will start from the design of chiral emissive gelator molecules
and then provide the examples of CPL from several typical gelator molecules and
their assemblies.
11.2 Design of the Chiral Gelator
The discovery of the gelator was fortuitous in the early stage of the development
on supramolecular gels. However, it becomes now possible to design the gelator
molecules on purpose. Hinted from the notion of supramolecular synthon in crystal
engineering and synthon in organic synthesis, we proposed a concept of gelaton
to the design of the gelator [19]. A gelator molecule can be illustrated as in Fig. 11.3.
A gelaton is defined as a special molecule or a structural unit that can be used to
formulate the supramolecular gelator and/or gels. Through the covalent bond of the
gelaton with certain fluorophore via a linker, it is easier to design the chiral gelator
for CPL. Fortunately, many of the gelatons are chiral. Figure 11.3 illustrates several
typical gelatons for the design of the gelator molecules, which will be useful for
Fig. 11.3 Three main parts of gelator and some typical gelatons [19]. Copyright 2018, The Royal
Society of Chemistry
252
T. Zhao et al.
gelator, while the fluorescence (comes or originates) from the nonchiral fluorophore.
The third case is the achiral chromophore without any chiral unit. In molecular state,
it does not show any CPL activity. However, upon gelation, symmetry breaking
occurs and the CPL could also be obtained.
In this chapter we will start from the design of chiral emissive gelator molecules
and then provide the examples of CPL from several typical gelator molecules and
their assemblies.
11.2 Design of the Chiral Gelator
The discovery of the gelator was fortuitous in the early stage of the development
on supramolecular gels. However, it becomes now possible to design the gelator
molecules on purpose. Hinted from the notion of supramolecular synthon in crystal
engineering and synthon in organic synthesis, we proposed a concept of gelaton
to the design of the gelator [19]. A gelator molecule can be illustrated as in Fig. 11.3.
A gelaton is defined as a special molecule or a structural unit that can be used to
formulate the supramolecular gelator and/or gels. Through the covalent bond of the
gelaton with certain fluorophore via a linker, it is easier to design the chiral gelator
for CPL. Fortunately, many of the gelatons are chiral. Figure 11.3 illustrates several
typical gelatons for the design of the gelator molecules, which will be useful for
Fig. 11.3 Three main parts of gelator and some typical gelatons [19]. Copyright 2018, The Royal
Society of Chemistry
252
T. Zhao et al.